New Attachment Allows Ground-Based Telescopes To View Exoplanets With Precision

Researchers from Pennsylvania State University have come up with an inexpensive telescope attachment that allows for unprecedented precision in observing exoplanets by ground-based telescopes.

According to Science Daily, the Penn State astronomers teamed up with researchers from Rochester, New York-based RPC Photonics to create “beam-shaping” diffusers. These are micro-optic devices that spread incoming light across an image and reduce the distortion created by the Earth’s atmosphere that could compromise the precision of exoplanet observations from ground-based telescopes.

“This inexpensive technology delivers high photometric precision in observations of exoplanets as they transit — cross in front of — the bright stars that they orbit,” explained lead author Gudmundur Stefansson, a graduate student at Penn State.

“This technology is especially relevant considering the impending launch of NASA’s Transiting Exoplanet Survey Satellite (TESS) early in 2018. It is up to ground-based facilities to rapidly and reliably follow-up on candidate planets that are identified by TESS.”

Stefansson’s fellow study author, Suvrath Mahadevan, explained that the beam-shaped diffusers are telescope attachments created by means of a delicate, “precise” nanofabrication process. Surface patterns are written in either one of two methods — by writing them precisely on a plastic polymer on a glass surface, or by directly drawing them on the glass. The patterns are made up of micro-scale structures that are designed to transform the varying light input from stars into a more stable, predefined form spread over the pixels of a telescope camera.

As explained by the International Business Times, it is possible to use focused ground telescopes for viewing exoplanets as they cross the path of their host stars, but images taken by these instruments tend to be of varying size and intensity. It is also possible to intentionally defocus in an attempt to spread the light out more evenly, but that doesn’t eliminate the fluctuations in size and intensity. But with the help of the new telescope attachment, images are much clearer and precise.

The diffusers were tested on three ground-based telescopes, including the Hale telescope in California. [Image by Fred Greaves/AP Images]

The researchers used the beam-shaping diffusers on three ground telescopes — Penn State’s own 0.6m telescope at the Davey Lab Observatory, the Hale telescope at California’s Palomar Observatory, and the ARC 3.5m Telescope at New Mexico’s Apache Point Observatory. Based on tests run on those three telescopes, the attachments were able to create more precise and stable images than focused or defocused images taken by conventional means.

Commenting on Penn State’s official press statement, study co-author Jason Wright said that the diffusers could be used for a variety of purposes, such as gathering precise measurements of the time it takes for exoplanets to orbit their stars. He added that this will help scientists determine their masses and compositions. Additionally, Wright believes that the telescope attachment could allow scientists to study exoplanets’ temperature structures and even help them find previously undiscovered planets in their solar systems.